In 1489, the Ottoman Prince Cem became a papal captive in Rome after years of ignominious peregrinations around the strongholds of France. As a rival claimant to his brother Bayezid II’s throne, Cem was a valuable hostage offering his captors “a compelling means to constrain the unbridled ferocity of the Turks against the Christians.”[i] Accordingly, his fate dominated the agendas of popes and kings until his death in 1495 and prompted a period of intense Ottoman diplomacy with Italian courts. Among Bayezid II's new friends was Marquis Francesco II Gonzaga of Mantua (r. 1484-1519), a mercenary captain and avid horse-breeder. During repeated diplomatic embassies to Istanbul, Gonzaga offered luxury textiles, animals, and Italian-made armor in exchange for Ottoman horses in large numbers. Accordingly, in this paper, I adopt the Mantuan-Ottoman relationship as a point of entry into a re-assessment of this consequential period. Undertaking the first comprehensive study of Francesco II’s Ottoman diplomacy since 1965, I draw upon a substantial corpus of under-utilized and unpublished correspondence in Italian and Turkish from the Ottoman Archives and the Archivio Gonzaga in Mantua. I trace how Mantuan agents gained knowledge of the Ottoman court, built relationships with provincial and central office-holders, and shared information with a wide mercantile network around the Adriatic under Venetian tutelage. Then, I offer a re-assessment of the papacy's role in these relationships. Despite longstanding papal embargos on the provision of strategic goods to Muslim rulers, I argue that Pope Innocent VIII and Alexander VI did not forbid Francesco II's activities outright. Instead, they played an essential and changeable role in mediating Mantuan-Ottoman contact to benefit their own negotiations over Cem's captivity. Synchronic and fine-grained, the view of Ottoman-Italian diplomacy visible from Mantua enriches not only our understanding of the 'Cem crisis' but also aids the ongoing revisionist interpretation of Sultan Bayezid II's reign. While the sultan negotiated at a disadvantage during Cem's captivity, his rule overall constituted not a 'weak link' but rather a period of administrative and cultural consolidation that continued the intense material exchanges with Italy begun during the reign of the more cosmopolitan Mehmed II. From Mantua to the Mamluk Sultanate, then, diplomacy helps situate Bayezid II more fully in an entangled history of the early modern Eastern Mediterranean. [i] Brief of Alexander VI to King Charles VIII of France, August 5, 1495 quoted by Sigismondo dei Conti da Foligno (my translation).